Smoke simulation "Bake" is missing (or moved?) from 2.8.0 to 2.8.2
It's now under Settings : Bake Data / Free Data.
Blender 2.82 use a brand new simulation engine (Mantaflow) for fluids and smoke, so any tutorial prior to this version is outdated.
For the given screenshot Cache &gt; Type change to Final then the Bake option appears below.